Error frame

Windows® Compatible Software for Displaying CAN Messages
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Tesmec
Posts: 6
Joined: Tue 10. May 2016, 23:20

Error frame

Post by Tesmec » Tue 10. Aug 2021, 22:47

Hello folks, I'm investigating a random issue that affect a j1939 bus. From time to time the bus stop working properly, the bus load reach 95% and a sequence of error frames is broadcasted. Can anyone explain if is possible to get any clue on the issue decodic the error frames? If yes, how could I decode them?
Attached part of a trace where the error frames show up.
Any help is appreciated.
Attachments
Trace with error frames.trc
(737.92 KiB) Downloaded 31 times

M.Heidemann
Sales & Support
Sales & Support
Posts: 673
Joined: Fri 20. Sep 2019, 13:31

Re: Error frame

Post by M.Heidemann » Wed 11. Aug 2021, 08:06

Hello,

You can always refer to the PEAK-Trace format description:

https://www.peak-system.com/produktcd/P ... Format.pdf

In your case, please look up format-version 2.0 (Page 112 of the document), which is used by PCAN-View.

Your trace shows form-errors, which do occur if the CAN-controller detects an invalid value
in of the CAN-Frames expected fields.

There are multiple possible causes for this, please check the following:

- Does the used bitrate match on all devices on the bus? (Also check the used sample-point)
- Is you CAN-Bus properly terminated? (120 Ohm on both bus ends, you should have ~60 Ohms between CAN-high and CAN-Low on the bus in an unpowered state)
- Check your cabling for possible damages


Please report back to us with your findings.

Best Regards

Marvin

Tesmec
Posts: 6
Joined: Tue 10. May 2016, 23:20

Re: Error frame

Post by Tesmec » Wed 11. Aug 2021, 14:22

Hello Marvin,
thanks for the quick response.
After several hours of investigation we did find the cause, it was a connection for a spare node, apparently well realized and properly capped, full of mud and moisture.
In certain conditions, not continuosly, the bus was reaching 95% load and voltage CANH-GND a value of 6.5V.
Hope this experience will help other people in their troubleshooting activities.
Regards.

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